Thermoelectric generator



Feb. 2 1927.

2 N. H. ADAMS IHERMOELECTRIC GENERATOR Filed June 22, 1925 2 Sheets-Sheet 1 Inventor; Nuth an H. Adams,

" His Attorney.

1,618,745 1927- N. H. ADAMS THERMOELECTRIC GENERATOR Filed June 22, 1 925 2 Sheets-Sheet 2 57/ O i /6 0'50 30 00 I 80 0 0 w 20 0/ 8 O0 0 80 08 O 0 8 v 80 a;

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WI? H in 2 if a; OO 6/ OO( 6 1T 7 319 W w 55 55 6/ 0 35 0 F 21 :2 I 50 45 2 6 lnven Patented Feb. 22, 1927..

NATHAN H. ADAMS, OF SCHENECTADY, NEW YORK, .ASSIGNOR T0 GENERAL ELECTRIC CONT-ANY, A CORPORATION OF NEW YORK.

THERMOELECTRIC GENERATOR.

Application filed June 22, 1925. Serial No. 38,696.

My present invention relates to improvements in thermoelectric generators of a type adapted for operating small electr cal apparatus such as the space current devices used in radio broadcast reception.

it is one object of my invention to provide a thermoelectric generator having a relatively small number of parts. It is a further object of my invention to provide an improved form of radiator so that the proper ditl'erence in temperature may be maintained between the hot and cold unctions of the thermopiles comprising the thermoelectric generator. A further ob ect of my invention is to provide improved means for electrically connecting the thermopiles comprising the thermoelectric generator, and for supporting the thermopiles and heater element in proper relation to one another. The particular type of thermop le employed in connection with my present. invention, together with the method ot l'tllllleating the same is disclosed in my copending applications, Serial Nos. 19,732 and 19,733, filed March 31, 1925.

The novel features which I believe to be characteristic of my invention are set forth with particularity in the appended claims. My invention itself, however, both as to its organization and method of operation will best be understood by reference to the following description taken in, connect1on with the accompanying drawing in which Fig. 1 represents a plan view of the thermoelectric generator with the cover therefore removed; Fig. 2 represents a central, vert1cal cross section of the device; Fig. 1s a perspective view of the thermoelectrlc generator, some parts being shown broken away; Fig. 4 is an elevation of one of the cooling plates of the convector or radiator; Fig. 5 is a perspective view, partly broken away, of the heater unit: Fig. 6 is a vertical cross section of the supporting plug member; Fig. 7 is a horizontal cross section of the thermoelectric generator, partly broken away showing the formation of the ends of the thermopiles including the hot junctions, and the arrangement of the heater unit between the opposed thermopiles; Fig. 8 is a detail view showing the manner of insulating the busbar connecting the two thermopiles.

Referring to the drawin I have indicated at 1 and 2 a pair of oppositely arranged thermopilcs having grooved ends 3 and 4.- (see Fig. 7) at that portion of each thermopile which includes the hot junctions. A heater element 5, of the type disclosed in my eopending application, Serial No. 12,733, is arranged between the two thermopiles and separated therefrom by flanged strips 6 of mica or similar insulation.

A radiator or convector 7 is associated with the cold junctions of each thermopile. Each radiator includes a pair of opposed sections 8 and 9 (Fig. l) and each section includes a plurality of substantially rectangular metal plates 10 (Fig. 4) riveted together at one side thereof and having grooves 11, 12 and 13 cut in one edge of each plate. The plates 10 are made of aluminum, although copper or any suitable metal may be employed if desired. An outside end plate 14, and a plurality of relatively short end plates 15, are riveted to each radiator adjacent one edge thereof and extend slightly beyond the radiator, as clearly shown in Figs. 2 and 8. A plurality of small rectangular plates 16 cooperate with the extensions of end plates 14 and 15, and are engaged by a screw 17 by means of which the distance between the sections of the radiator may be properly adjusted and the thermal contact of the radiator and thermopile varied.

Each end plate let closes one end of the slots 11, 12 and 13, and with the radiator sections, forms a pocket within which a thermopile rests. The top and bottom plates of the thermopile are insulated from the radiator by means of mica or similar insulating strips 18 which fit within slits 19 cut at the upper and lower end of each slot 12. Similar mica. strips 20 and 21 are inserted between the sides of a thermopile and its associated radiator and between the end of the thermopile and the end plate 1% respectively. The strip 20 is attached between end plate 14- and the edge of one of the convectors and bent into the slot 12 as indicated in Figs. 3 and 8.

A grooved insulating block 22 is placed in each slot 11 and 13, and extends slightly beyond the slot as indicated in Fig. 8. Two opposing grooves, in blocks 22, form an opening through which a conductor 23 extends. Each end plate 14 is slightly recessed as indicated at 24, in order to insulate completely conductor 23, and a narrow stri of insulation is pressed between each 0 the end plates 14.

Conductor 23 is provided with a central circular portion 26 and with screw threaded end portions 27. A small rectangular metal plate 28 is fitted on each end of the conductor 23. One plate 28 is threaded to conductor 23 while the other plate fits loosely thereon. Each plate 28 is insulated from end plates 14 by means of an insulating strip of mica or similar material 29.

The upper end of each thermopile is connected to conductor 23 by a flexible lead 30 which extends through the insulating strip 25 and is clamped at one end between the plate 28 and nut 31. By adjusting one of the nuts 31 on the conductor 23, the heater :lement 5 may be firmly clamped between :he thermopiles 1 and 2, and the latter held irmly in position. If desired both plates 28 nay fit loosely on conductor 23 or may be :crew threaded thereto.

A similar conductor 32 extends through .he insulators in slots 12, near the base of sach thermopile, and is provided at one end vith an adjustable nut 33 corresponding to iut 31 and a loose plate 28. A flexible conrector 34, connected to one of the thermoiiles, is clamped between nut 33 and plate 58. The other end of the conductor 32 is )rovided with a screw threaded portion to vhich a plate 28 is attached. A socket 35, raving a pair of contactors, is mounted on he plate 28 and is adapted to cooperate with plug 36. Conductor 32 is connected to one f the contactors of socket 35 while the other ontactor is attached by flexible connector 7 to the lower end of one of the thermo iles. With the connections shown the ther- 10 iles are permanently connected in series.

onductors 23 and 32 are each provided 'ith screw threaded openings through which :rews 38 extend and engage insulating locks 39 which are associated with the top nd bottom members of each thermopile. y adjusting screws 38, the elements of each iermopile are pressed toward one another, ad the associated thermopile firmly clamped etween conductors 23 and 32.

The heater 5 comprises a central insulatlg core 40 of soapstone or similar insulat- 1g material, which is grooved, and on which wound a wire 41.. Each end of the insutor is reduced in diameter, as shown in in )pending application, Serial No. 19,733, id is provided with a metal ferrule 42 havig an extension or lug 43. The ferrule is ads from a fiat L-shaped piece of metal, [ch as nickel or similar material, which is ound around the insulator 40, and line elded at its ends as shown at 44. As in y copending application, the heater wire wound for some distance on the ferrule 2. and is spot welded thereto at its ends.

The heater 5 together with the hot junctions of the thermopile are surrounded by a heat conservin device comprising a hollow alundum cylinder 45 which is slotted at 0pposite points so as to slide over the narrow portion 46 of each thermopile. The cylinder is filled with mineral wool or a similar material 47. The cylinder 45 is provided with a cover 48 of insulating material, which is fastened to the circular portion 26 of conductor 23 by a screw 50, and which has a central opening 49 through which the lug 43 extends.

An electrical attachment, comprising a split plug 51, made of insulating material, 1s employed to supply current to the heater wire 41, and also to support the thermoelectric generator. The plug is split longitudinally and the upper section is provided with an o 'iening 52 adapted to receive the extenslon 43 on the lower ferrule 44 of the heater element 5. The plug is provided with two terminals 53 and 54. Terminal 53 is flattened at one end and attached to the. lower extension 43 by means of a bolt or screw 55. The other terminal 54 is L-shaped and extends through a small circular opening 56 in the upper part of the plug. The upper end of terminal 54 is fastened to the upper extension 43 of the heater element by means of a nut 57. If desired the opening 52 may be restricted so that the heater 5 may be supported on the edge portion thereof.

The lower conductor 32 is fastened to the plug 51 by means of screws 58, which are countersunk in order to avoid short circuiting the generated current through the metal base plate 59, to which the thermoelectric generator may be attached. The base plate 59 is made of perforated metal and is secured to the plug 51 by means of screws 60 which engage nuts 61 embedded in the lower member of the plug. A screw 62 extends through the base plate and plug and secures thereto a metallic collar member 63.

The base plate 59 is provided at its four corners with small brass angles 64 to which a perforated box shaped metal cover 65 may be permanently connected in any suitable manner. The base plate 59 is mounted on blocks 66 suitable material. By means of the perforated metal casing and the blocks 66 the parts of the thermoelectric generator are not only protected from injury, but the circulation of air through the cooling lates and around the thermopiles is greatly acilitated.

What I claim as new and desire to secure by Letters Patent of the United States is 1. In a device of the class described, a convector including a plurality of relatively thin metal plates permanently united at one side thereof, each of said plates having a slot in one edge thereof, said slots being in which may be of rubber or anyalignment and adapted to accommodate a thermopile.

2. In combination, a thermopile, and a convector for said thermopile, said convector comprising a plurality of relatively thin metal plates, each of said lates having a plurality of slots in one e ge thereof, the slots in an one plate being in alignment with the slbts in the other plates, one of slots being adapted to accommodate said thermopile.

3. In combination, a thermopile and a convector for said thermopile, said convector comprising a plurality of oppositely arranged sections, each section including a plurality of relatively thin metal plates permanently united at one side thereof, each of said sections having a slot in said side adapted to accommodate the thermopile, and means for controlling the thermal contact between said sections and thermo ile.

4. In combination, a thermopile, and a convector for said thermopile, said convector comprising a plurality of oppositely arranged sections, said sections including a plurality of relatively thin metal plates, an end plate permanently connected to each of said sections, and extending slightly beyond said sections, and means cooperating with said end plates for controlling the thermal coptact between said sections and thermopi e.

5. In combination, a thermoelectric generator comprisin a pair of oppositely arranged thermopi es, a radiator associated with the cold junctions of each thermopile, and means cooperatin with said radiators for maintaining said t ermopiles rigidly in position, said means including a conductor electrically connecting said thermopiles.

6. In combination, a thermoelectric generator comprising a pair of oppositely arranged thermopiles, a plurality of conductors electrically connected with said thermopiles, and means for compressing said thermopiles between said conductors.

7. In combination, a thermoelectric generator comprising a plurality of oppositely arranged t ermopiles, a heater element between said thermopiles, and means for adjusting the position of said thermopiles with respect to said heater, said means including a conductor electrically connected to said thermopiles.

8. In combination, a thermoelectric generator comprising a plurality of oppositely arran ed thermopiles, an electric heater element Eetween said thermopiles, means adapted to maintain the thermopiles and heater in position relative to one another, and an electrical device connected to said means to provide a support for the generator, said device havin a plurality of terminals con nected to said heater.

9. In combination, a plurality of oppositely arranged thermopiles, a heater element between said thermopiles, a heat conserving element adapted to substantially enclose said heater element and the hot junctions of said thermopiles, and means for maintaining said thermopiles and heat c0nserving element in position, said means including a conductor electrically connected to said thermopiles.

10. In combination, a thermoelectric generator comprisin a pair of oppositely arranged thermopi es, an electric heater between the thermopiles, means for maintaining the thermopiles in engagement with the heater, and supporting means for the generator, said supporting means comprising a device arranged intermediate the ends of the generator and provided with terminals whereby current may be supplied to the heater,

In witness whereof, I have hereunto set my hand this 19th day of June, 1925.

NATHAN H. ADAMS. 

